JP2001-337110 Japan Sep. 28, 2001, and
JP 2002-298025 Japan Sep. 5, 2002 for Prior Foreign Application Benefits
Not Applicable
Not Applicable
1. Field of Invention
This invention relates to lens hoods that are mounted to camera lenses for use.
2. Description of Prior Art
There are widely known various types of lens hoods. One type of lens hoods is a tubular type hood that is mounted on a lens barrel or is screwed into a lens barrel thread. Other type of lens hoods is a panel type hood that comprises a flexible rod with a clamp at one end of the rod and a panel fastened to another end of the rod. In an operation state, the clamp is fixed to a camera body or its lens. Then, the panel is placed at a desired position between a light source and the lens by bending the rod. Other type of lens hoods is a bellow type hood that has a rectangular hood opening and is mounted on a camera or its lens then shields unnecessary light by adjusting the hood length.
In the case of the tubular type hood, a plurality of hoods, which is used for a plurality of lenses that has various focal lengths and barrel diameters, must be required. Therefore, a problem is that it is bulky. As for a light shield capability, a tubular type hood that has a circular hood opening is less effective than a lens hood that has a rectangular hood opening. In the case of the panel type hood, a problem is that it can shield only unnecessary light rays which direct at the panel surface, therefore, whose light shield capability is less effective than that of the tubular type hood or the bellow type hood.
In the case of the bellow type hood, it has an excellent light shield capability. However, a problem is that it has relatively complicated structure and is heavy and bulky, therefore, it requires longer mounting time and its operation is complicated.
As other types of known lens hoods, in which a single hood is capable to use for a plurality of lenses which has various focal lengths and barrel diameters, spring and screw mount type hoods are available. Each of the hoods has a hole with a diameter large enough to mount on various lens barrels. Each of the hoods is mounted on a lens barrel by either spring or screw means. In the spring mount type hood, a problem is that whose mechanical strength for mounting is relatively weak. In the screw mount type hood, a problem is that it is difficult to mount on a lens with precise alignment and the mounting operation is cumbersome.
An object of the present invention is to solve the above stated problems and provides a lens hood, that is extremely compact for transport, that can be quickly mounted, that offers an easy operation, and that has an excellent light shield capability.
An essence of the present invention is that the lens hood comprising an adapter module having a circular hole through which a lens is continuously fastened, an inner hood further comprising, a plurality of first panels connected each other along adjacent edges in a closed sequence, and front and rear openings, and the inner hood which fits the adapter module for detachable attachment.
Thus, in order to enable a single lens hood to be available for a plurality of lenses having various focal lengths and barrel diameters, first, modular structure, comprising two modules the adapter module and a hood module, is provided. Second, an identical attachment interface between the adapter modules and the hood modules is provided.
Third, it is arranged in such a way that a plurality of the adapter modules is always fastened respectively to a plurality of lenses having various focal lengths and barrel diameters. Thus, any of the hood modules, each of which has the identical attachment interface, can be attached to any of the adapter modules.
The hood module comprises the inner hood and an outer hood. The inner hood further comprises a plurality of the light shielded first panels hingedly connected each other along adjacent edges in the closed sequence. The opening of the inner hood at a lens side, that is a rear side, has the identical attachment interface. Any of the inner hoods is detachably attachable to any of the adapter modules.
The adapter module has the circular hole with a diameter large enough for a lens barrel to be continuously fastened. The adapter module complementary matches the rear opening of the inner hood as the identical attachment interface.
In order to make the hood module attachment operation easy and quick, a plurality of tapered bodies, each bent toward an optical axis and having a tip pointing toward a photographing object side and another end of the tip fastened to each vertex of the adapter module at a radial direction square to the optical axis, is provided to the adapter module.
To make the attachment securer, at least one hood lock is provided to the adapter module. At least one of the hood lock each comprises a first elastic member, at least one lock pin each having an oblique section at a tip and mounted on the first elastic member in a same direction, the first elastic member fastened at the optical axis side of the vertex of the adapter module as at least one of the lock pin each pointing toward a radial direction square to the optical axis and intersecting a plane configured by the vertices with the oblique section exposed to the photographing object side, and at least one of the lock pin each of which pushes an inside wall of the inner hood by the first elastic member when the attachment is made and is released when the first elastic member is pulled back to an opposite direction.
In order to make a hood length variable, the outer hood is provided to the hood module. The outer hood comprises a plurality of second panels connected each other along adjacent edges in the closed sequence, and front and rear openings, and the outer hood which fits the inner hood to make slidable double layer structure. The outer hoods comprises a plurality of the light shielded second panels hingedly connected each other along adjacent edges in the closed sequence. Thus, when the inner hood is securely attached to the adapter module, the outer hood is able to move along the inner hood to change the overall hood length.
In order to make the hood module, which has the double layer structure, foldable, for maintaining a gap between each of the connected adjacent edges of the second panels of the outer hood, a plurality of play members, each of which is provided between each of the connected adjacent edges of the second panels for maintaining the gap as each length of the play members is equal to a thickness of the inner hood in an folded state, is provided.
Next, a plurality of the second panels, each edge length square to the optical axis of which is defined as a perimeter of a contact plane of the inner hood to the outer hood is equal to a perimeter of an inside plane of the outer hood when the attachment is made, is provided. Thus, the hood module is able to be foldable while neatly slidable.
In a folded state, to reduce a total thickness of the hood module, the inner hood further comprises at least one depression each provided on each of the first panels at an outside surface. A space created by the depression can partially absorbs a thickness of an extension adjust. Thus, in a store state, the hood module can be folded for extreme compactness and transportability.
To secure the overall hood length at a desired position during an operation state, at the outer hood, at least one of the extension adjust is provided. At least one of the extension adjust each comprises a long plate, a friction plane at one surface end of the long plate, a rotation axis placed at a center of the long plate, and an elastic member urging the rotation axis to rotate, at least one long hole each of which is placed on each of the second panels square to the optical axis at the lens side, and the rotation ax is pivotally connected at a center of the long hole as the friction plane facing the optical axis as the elastic member functioning with the second panel of the long hole.
Always, at least one of the friction plane each is pressed by the elastic member against an outside surface of the inner hood, thus the outer hood position is secured, however, by applying pressure on another end of the long plate, a frictional contact is disengaged, then the outer hood becomes slidable.
To maximize a light shield capability of a hood, shape of the hood front opening has to match a film aspect ratio for use. For this reason, a plurality of projection members, each provided on each edge of the second panels at the photographing object side, is added to simulate the film aspect ratio.